1. Field of the Invention
The present invention relates to an injection system for a dual-fuel engine.
2. Description of the Prior Art
One example of a fuel injection system for a diesel engine of the heretofore known type is shown in FIG. 6. In this figure, reference numeral 101 designates a fuel tank, numeral 102 designates a fuel feed pump, numeral 103 designates a fuel injection pump main body, numeral 104 designates a plunger in the fuel injection pump, numeral 105 designates a barrel in the same, numeral 106 designates a delivery valve, numeral 107 designates an injection pipe, numeral 108 designates a fuel injection valve main body, numeral 109 designates an injection nozzle in the fuel injection valve, numeral 110 designates a needle valve in the same, numeral 111 designates a fuel reservoir in the same, and numeral 112 designates a spring in the same.
Since such fuel injection system for a diesel engine in the prior art is constructed with an object of injecting a single kind of fuel, in order to inject two kinds of fuel it is necessary to mix these two kinds of fuel preliminarily to feeding of the fuel, and it is impossible to inject the two kinds of fuel clearly separated from each other during an injection period.
Furthermore, in such fuel injection system in the prior art, there are shortcomings that if a hardly self-ignitable fuel such as aromatic oil, lower alcohol, etc., that is, a fuel having a low cetane number, is used in a diesel engine, then starting of the engine is difficult, even if the engine should be started, diesel knocking will occur and hence continuation of operation is difficult, and that such factors result in adverse effects upon a life of the engine.